callbacks

Tower.Model.Callbacks

Tower supports 3 main callbacks:

• before
• around
• after

The following callbacks are implemented:

• @after "initialize"
• @before "validate"
• @after "validate"
• @before "create"
• @after "create"
• @before "update"
• @after "update"
• @before "save"
• @after "save"
• @before "destroy"
• @after "destroy"

Callbacks are available on any model.

Define a callback with the callback phase helpers

class App.Post extends Tower.Model
  @field "title", type: "String"
  @field "slug", type: "String"
  
  @before "save", "generateSlug"
  
  generateSlug:  ->
    @set "slug", @get("title").replace(/[^a-z0-9]+/, '-').toLowerCase()

Define the phase and callback directly

class App.Post extends Tower.Model
  @field "title", type: "String"
  @field "slug", type: "String"
  
  @callback "save", "before", "generateSlug"
  
  generateSlug:  ->
    @set "slug", @get("title").replace(/[^a-z0-9]+/, '-').toLowerCase()

Define callbacks with anonymous functions

class App.Post extends Tower.Model
  @field "title", type: "String"
  @field "slug", type: "String"
  
  @before "save", ->
    @set "slug", @get("title").replace(/[^a-z0-9]+/, '-').toLowerCase()

Callbacks can be asynchronous

If you have a callback that executes asynchronous code, you can add the callback argument to your function, and call it when complete:

class App.Post extends Tower.Model
  @field "title", type: "String"
  @field "url", type: "String"
  
  @before "save", "scrapeWebsite"
  
  scrapeWebsite: (callback) ->
    SomeCrawler.scrapeHTML @get("url"), (error, html) ->
      callback(error)